(1) Field of the Invention
The present invention relates to a process for the synthesis of 2-vinyl-4,6-diamino-S-triazine (hereinafter referred to as "VT"). More particularly, the present invention provides a process for preparing VT in large quantities at low costs.
(2) Description of the Prior Art
VT is a compound which is valuable as a comonomer, and it is known that if a diamino-S-triazine is introduced into side chains of a polymer, the softening point and glass transition point of the polymer are greatly elevated as compared with those of the non-modified polymer, and the specific gravity is increased and the solubility is prominently changed (see, for example, Nadao and Kakurai: Collection of Polymer Theses, 32, 308 (1975) and T. Seo, K. Abe, H. Honma and T. Kakurai: Polym. Prepn., 20, 661 (1979)).
Several processes as described below are known for the synthesis of VT. Namely, there can be mentioned a process in which biguanide is reacted with acrylic acid chloride (C. G. Overberger et al: J.A.C.S., 80, 988 (1958)), a process in which dicyandiamide is reacted with .beta.-dimethylaminopropionitrile (French Pat. No. 1,563,255 (1967) to Hoechst AG), a process in which 1,2-di(4,6-diamino-S-triazinyl-(2))-cyclobutane is heated at 320.degree. C. under reduced pressure (Japanese Patent Publication No. 35068/71 to Asahi Kasei), and a process in which 2-.beta.-methoxyethyl-4,6-diamino-S-triazine is heated at 350.degree. C. in a nitrogen current (Suddeutsche Kalkstickstoff Werke A.G.: Offen. 2, 135, 881 (1973)).
However, these known processes are defective in that the starting materials are expensive or the reaction procedures are complicated. Accordingly, none of these known processes are suitable for industrial working.